Bear Lake Final Results Portage County Lake Study March 31, 2005 University of Wisconsin-Stevens Point, Portage County Staff and Citizens What can you learn from this study? You can learn a wealth of valuable information about: Critical habitat that fish, wildlife, and plants depend on Water quality and quantity of your lake The current diagnosis of your lake good news and bad news What can you DO in your community? You can share this information with the other people who care about your lake and then plan together for the future. Develop consensus about the local goals and objectives for your lake. Identify available resources (people, expertise, time, funding). Explore and choose implementation tools to achieve your goals. Develop an action plan to achieve your lake goals. Implement your plan. Evaluate the results and then revise your goals and plans. 1
2
Bear Lake ~ Location Bear Lake Six miles west of Amherst in the Town of Stockton Surface Area: 29 acres Maximum Depth: 28 feet Lake Volume: 237 acre-feet Water Flow Bear Lake is a seepage lake Water enters Bear Lake primarily from groundwater, with some runoff, and precipitation Water exits the lake to groundwater The fluctuation of the groundwater table significantly impacts the water levels in Bear Lake 3
Bear Lake ~ Land Use in the Surface Watershed Surface Watershed: The land area where water runs off the surface of the land and drains toward the lake. Surface Watershed: 253 acres Bear Lake Rd Current Predominant Land Use Around the lake: shrub cover, agriculture, and residential In the watershed: forest cover and conifer plantation Standing Rocks Rd Acres 140 120 100 80 60 Surface Watershed Land Use Surface Watershed Land Use Forest is the dominant land cover in the watershed. Sometime after 1968 a large area of forest was cut and shrubs dominated the land cover until the forest returned 40 20 0 Residential Institutional Transportation Non-Irr. Cropland Farmsteads Forested Conifer Plantation Herbaceous/Shrub Water 1948 1968 1990 2002 Non-irrigated cropland has increased slightly since 1948 Residential land use has increased slightly since 1990 4
Bear Lake ~ Land Use in the Groundwater Shed Groundwater Shed: The land area where water soaks into the ground and travels underground to the lake. County B Current Predominant Land Use Major land uses in the groundwater shed are forest, non-irrigated agriculture, shrub cover, and conifer plantation Tower Rd Acres 160 140 120 100 80 60 40 20 0 Residential Institutional Transportation Communication and Utilities Groundwater Shed Land Use Non-Irrigated Crop land Pemanent Pasture Confined Animal Operations Forested Shrub Cover Water Bodies 1948 1968 1990 2002 Groundwater Shed Land Use Forest and nonirrigated cropland have dominated the land use since 1948 Residential areas have remained a small fraction of the land use over time Permanent pasture appeared in the watershed in 1990 and has increased since then 5
Bear Lake ~ Taking a closer look (Within 1,000 feet of the lake) 2 4 1 3 Noted Features 1000 Foot Buffer Residential Area 1960 Lake Edge 1960 Points of Interest 1. The blue line represents the size of the lake in 1960. 2. As you can see from the 60 photo, much of the surrounding area was farmed. Most of this cropland has reverted back to forest. 3. Development from forest land to county park - ski - hill. 4. This is the delineated 1000 foot buffer. 1960 Air Photo Note: Lake level in 2000 is still well below other years. buffer. - 6
Bear Lake ~ Taking a closer look (Within 1,000 feet of the lake) Percentage Land Cover Within 1000 Foot Buffer 60% 50% 40% 30% 20% 1938 2000 10% 0% Forest Impermeable Surfaces Developed Parks/Schools Cropland 7
Bear Lake ~ Water Quality Total Phosphorus In more than 80% of Wisconsin s lakes phosphorus is the key nutrient affecting aquatic plant and algae growth. Once in a lake system phosphorus levels are difficult to reduce, so limiting phosphorus input is key. Phosphorus at levels above 30 parts per billion (ppb) can lead to nuisance aquatic plant growth and accelerate a lake s change from oligotrophic to eutrophic. Sources of phosphorus include septic systems, detergents, animal waste, farmland and storm sewer runoff, soil erosion, and fertilizers for lawns, gardens, and agriculture. Oligotrophic Lakes Common uses: Swimming Skiing Boating Vegetation of oligotrophic lakes: Very little vegetation Mesotrophic Lakes Common uses: Boating Fishing Vegetation of mesotrophic lakes: Increased vegetation Occasional algal blooms Eutrophic Lakes Common uses: Fishing Wildlife watching Vegetation of eutrophic lakes: Lots of aquatic plants Frequent algal blooms Winterkill problems are most likely in shallow lakes. 8
Bear Lake ~ Water Quality Average Total Phosphorus Levels Concentration (ppb) 35 30 25 20 15 10 5 0 Eutrophic Mesotrophic Oligotrophic Bear Lake Historic Average 2002-03 Average The graph to the left shows total phosphorus levels measured when the lake was well mixed (overturn). Phosphorus levels in Bear Lake in 2002-03 were slightly lower than average historic levels. Compared to other seepage lakes in the county Bear Lake has higher levels of phosphorus than the 25 ppb average. Levels of phosphorus above 30 ppb are high enough to categorize a lake as eutrophic, making it subject to aquatic plant growth that results in better fishing and wildlife viewing than swimming. Overturn: uniform temperature from top to bottom in the lake. Water Clarity Water clarity (Secchi disc depth) is an indicator of water quality. The two main components affecting water clarity are materials dissolved in the water and materials suspended in the water. Water clarity can indicate overall water quality, especially the amount of algae and suspended sediment present. Depth from surface (ft) 0 5 10 15 20 Bear Lake The water clarity in Bear Lake is considered fair. The average Secchi depth reading for similar lakes in the region is 9-10 feet; Bear Lake appears to have similar clarity to this. The water clarity of Bear Lake during 2002-03 growing seasons was poorer than the historic growing season average. The month of August shows the best water clarity and the month of June the poorest. These fluctuations throughout the summer are normal as algae populations and sedimentation increase and decrease. May June July August Sept. Historic Average Historic Maximum 2002/2003 Average Historic Minimum 9
2002 Amphibian Distribution at Portage County Lakes This summary provides preliminary information on the amphibian species present and their distribution at the twenty-nine Portage County lakes. Surveys were conducted from April 2002 - August 2002, the typical breeding period of the frogs and salamanders found in the county. Twelve frog species have been documented in Wisconsin, nine of which currently inhabit Portage County: American toad, chorus frog, spring peeper, eastern gray treefrog, Cope s gray treefrog, green frog, pickerel frog, northern leopard frog, and wood frog. Historically, Blanchard s cricket frog inhabited Portage County but is believed to now exist only in southeastern Wisconsin. Of all species believed to inhabit Portage County, only the pickerel frog was not found during the spring and summer of 2002. The pickerel frog has been listed as a species of special concern in Wisconsin. No new species to Portage County were recorded in 2002. Seven salamander species have been documented in Wisconsin, all of which currently inhabit Portage County: blue-spotted salamander, spotted salamander, tiger salamander, central newt, mudpuppy, northern redback salamander and four-toed salamander. The four-toed salamander is listed as a species of special concern in Wisconsin. Large sections of continuous natural shoreline on lakes are ideal habitats for frog and salamander populations. Natural areas with large amounts of submergent, emergent and floating-leaf vegetation provide protection for amphibians. Many species also use the vegetation for attachment of eggs during the breeding season. Green frogs, bullfrogs, pickerel frogs and leopard frogs depend on the shoreline area throughout the year. In contrast, American toads, spring peepers, tree frogs, wood frogs and chorus frogs depend on the shoreline area in the spring for breeding and then move to other areas for the rest of the year. Undisturbed areas of shoreline that are also connected to large natural upland areas provide ideal habitat for many amphibian species because they lessen frogs exposure to predators. Many frog and salamander species migrate to the lakes in the spring to breed and spend the summer months foraging in the uplands. Many amphibian species will also over winter in the uplands. Chorus Frog Spring Peeper Eastern Gray Treefrog Northern Leopard Frog Wood Frog American Toad Green Frog Cope s Gray Treefrog Blue-spotted Salamander Northern Redback Salamander 10
Bear Lake ~ Frogs and Turtles Bear Lake Frogs and Turtles Number of frog species: 5 Frog species observed: spring peeper, chorus frog, green frog, gray treefrog, American toad Location of primary habitat: east side of lake Key features of habitat: protected areas of marsh with large amounts of submergent, emergent and floating-leaf vegetation Number of Turtle species: 1 Map Key Red outlined areas = primary frog habitat Good news Large areas of natural habitat, houses are present on the lake but shoreline development has been kept to a minimum Turtle species observed: painted turtle 11
Bear Lake ~ Shoreline Vegetation Frogs and toads depend on shoreline and aquatic vegetation for: attachment of eggs during the breeding season, shelter for adults throughout the spring and summer, food for larvae, habitat for prey, and slowing evaporation and moderating temperature fluctuations. Bear Lake Green Frog Habitat Frogs are commonly found in areas with large amounts of tree cover, aquatic plants, leaves, and downed branches, characteristics typical of natural areas. Frogs are not frequently found in sandy areas or open water, characteristics typical of altered areas. Though amphibians use drier prairies and woodlands near lakes and wetlands, this study focused on areas reaching from 16 feet into the lake to 33 feet inland. Poor 13% Excellent 5% Green frogs are used as an indicator for the health of aquatic life in Wisconsin lakes because they are abundant, live in many cover types, and remain along the edge of the lake throughout the spring and summer. While other amphibians may require more specific cover types, the green frog habitat is a useful indicator. Some cover types (as shown on map above) are better than others for green frogs. Specifically: Excellent green frog habitat = cover types 1 and 2 Adequate green frog habitat = cover types 3, 4 and 6 Poor green frog habitat = cover types 5, 7 and 8 Lakes with larger amounts of good green frog habitat will likely support more amphibians and more species of amphibians. Likewise, amphibians are more likely to be harmed or eliminated with increasing shoreland development. Adequate 82% Best Green Frog Habitat: Ebert Lake 33% excellent habitat + 67% adequate Worst Green Frog Habitat: Helen Lake 2% excellent habitat + 6% adequate + 92% poor 12
Bear Lake ~ Fish Bear Lake Fish Number of observed species: 10 Species observed to date: This chart represents all species detected, by decade, in Bear Lake since censusing began. Data before 2002 was collected by the Wisconsin DNR and 2002/2003 data was collected by UW-Stevens Point. X represents a decade when the species was detected. 1960's 1980's 2000's Bluegill X X X Bluegill/Pumpkinseed hybrid X Pumpkinseed X X Green Sunfish X Warmouth X X Largemouth Bass X X Black Crappie X X X Yellow Perch X X X Northern Pike X X X Yellow Bullhead X Bullhead sp. X White Sucker X Blackchin Shiner X Central Mudminnow X 13
Substrate: Bottom substrate is mostly muck and sand with one area of gravel and another with widely scattered boulders. The area of sand and gravel is unique and should be protected from disturbance. The gravel or mixed sand and gravel is preferred substrate for largemouth bass nest building. The sandy shoreline is critical for sustaining reproduction in blackchin shiner. Vegetation: Emergent sedges and rushes in shallow water along all but the northern shore are the preferred spawning habitat for northern pike. The water lilies and pondweed along the north shore provide excellent habitat for largemouth bass and northern pike to ambush prey. There was no woody cover noted on this Bear Lake, which would benefit fish by providing year-round cover. 14
Bear Lake supports a warm water fish community. Ten species of fish were collected from Bear Lake in 2002-2003 compared to 9 from historical records. Species not previously reported from this lake include yellow bullhead, blackchin shiner, central mudminnow and the bluegill/pumpkinseed hybrid. Species lost from the lake or not detected include pumpkinseed, green sunfish and white sucker. The most abundant species in Bear Lake as in other Portage County lakes is the bluegill. There are no official records of stocking Bear Lake but it would be unusual if this public access lake had not received state propagated fish at some time. A 1962 WDNR report indicated an excellent bluegill and crappie sport fishery present in the lake with largemouth bass and northern pike present. A WDNR survey performed in 1985 again substantiated the excellent bluegill and black crappie population. The report also noted that Bear Lake had the largest pumpkinseed fishery seen in any central Wisconsin Lake with individuals up to 9.5 inches (possible state record at the time). In the 2002-2003 survey more sizable largemouth bass were caught in Bear Lake than in any of the other lakes sampled, but the notable population of pumpkinseed sunfish had disappeared apparently lost though hybridization with bluegill. Populations of pumpkinseed sunfish appear to have significantly decreased or have been lost to hybridization in a number of Portage County lakes. These species commonly hybridize in some lakes and remain isolated in others. Hybridization between sunfish in some lakes has been attributed to overcrowding, limited spawning habitat or environmental disturbance. The average size of these hybrids and bluegill was small indicating overcrowding and possible stunting, a typical condition in most of the lakes sampled. Black crappie appear to be less abundant and smaller in size than in the past, but anglers reportedly still specifically fish the lake for crappie. The warmouth sunfish is near the northern extent of its range in Wisconsin and continues to be found in Bear Lake. It is uncommon to rare throughout its range in Wisconsin, but appears to have become well established in a number of the small lakes in Portage County that lie near the headwaters of tributaries to the Wolf River. It is reported to prefer densely vegetated areas and has a greater tolerance to low dissolved oxygen than other species of sunfish which may account for its continued presence in Bear Lake. Newly reported species in this lake such as the yellow bullhead and central mudminnow are common residents of central Wisconsin lakes and streams. The blackchin shiner is a glacial relict of lakes and streams in Wisconsin. It is rare or endangered throughout much of its range in the U.S. and has been extirpated in some states. It was once much more abundant throughout Wisconsin but has been eliminated from most streams because of increased turbidity. Its distribution is mostly restricted to small relatively undisturbed glacial lakes. Because Bear Lake does not have an inlet or outlet it is possible a small undetected population of this species has existed here in relative isolation since glaciation. Although it is not classified as a rare fish in Wisconsin, a potentially isolated population such as this is possibly unique and should be given consideration for protection. 15
Bear Lake ~ Aquatic Plants Aquatic plant surveys were conducted in each lake. More detailed information is available in the final report. Aquatic Plant Survey There were 85 species of vascular plants found in Bear Lake or rooted in wet or water logged soil on the shore and in the small adjacent wetlands. This is well above average when compared to the other Portage County lakes. The aquatic and wetland flora of Bear Lake is remarkably large and diverse, including several relatively rare species, although no threatened or endangered have been found. The submersed vegetation is rather dense, but not extreme. Dominant submersed plants include common milfoil, several pondweeds, Canadian waterweed, bush-pondweed, and coontail. Free-floating carnivorous bladderworts are unusually common. The shoreline includes dense concentrations of shallow water submersed plants and emergents such as water-marigold, spikerushes, and three-way sedge. Water levels have fluctuated greatly over the years, with plants which can adapt to being submersed or rooted on moist soil, such as needle spikerush, amphibious smartweed, and brown-fruited rush, thriving regardless whether water is exceptionally high or exceptionally low. The richest areas for wetland plants are on the north shore near the boat landing, and in small areas on the east and west end of the lake. Several typical bog species were found here in the late 1960's and early 1970's; most of these species have not been seen in recent years. As of 2003 invasive alien species were not abundant in or around the lake; reed canary-grass is spreading in wetland areas, but not yet dominant. However, one plant of Eurasian milfoil was found floating in the lake in 2003, and removed. It may be too much to hope for that this milfoil plant had just arrived and was eliminated before it could become established. Bear Lake needs to be monitored carefully to prevent the establishment of Eurasian milfoil. Invasive Exotic Aquatic Plants Invasive species displace native species, disrupt ecosystems, and affect citizen s livelihoods and quality of life. They hamper boating, swimming, fishing, and other water recreation, and take an economic toll on commercial, agricultural and aquatic resources. (Wisconsin DNR) Aquatic plants surveys revealed that some of the lakes in the study have invasive aquatic plants present. Eurasian milfoil (Myriophyllum spicatum) was present in Bear Lake, Lake Emily, Lake Joanis, Jordan Pond, McDill Pond, Springville Pond and Thomas Lake. Curly leaf pondweed (Potomogetan crispis) was identified in Spring Lake and Amherst Millpond. Contact the Portage County Land Conservation Department for additional information. 16
Bear Lake ~ What can you do? A lake is a magnificent water resource. The quality of its water is a reflection of what happens on the land that surrounds it. Lake Users: Run boat engines efficiently. Observe no/low wake zones. Refuel away from water. Dispose of trash property Remove all aquatic plants from boats and trailers. Project support provided by: Wisconsin DNR Lake Protection grants UW-Stevens Point Portage County Portage County Citizens Study Contacts: Portage County: Steven Bradley at 346-1334 UW- Stevens Point: Nancy Turyk at 346-4155 Land Owners: Control soil erosion. Keep livestock out of lakes and streams. Control manure runoff. Carefully manage nutrients and pesticides. Learn to identify and look for invasive species. Home Owners: Leave natural vegetation buffers in place or replace them if they have been removed. Eliminate the use of fertilizer or use low/no phosphorus fertilizer. Eliminate or minimize use of pesticides. Control soil erosion. Clean up after pets. Learn to identify and look for invasive species. 17
Bear Lake ~ Primary Researchers Algae Dr. Bob Bell Aquatic Plants Dr. Robert Freckmann Birds Dr. Tim Ginnett Brad Bulin (Graduate Student) Fish Dr. Ron Crunkilton Land Use Coverages/Watersheds Steve Bradley (Portage County Conservationist) Planning Assistance Lynn Markham Mike Hansen Reptiles and Amphibians/Near Shore Habitat Dr. Erik Wild Rori Paloski (Graduate Student) Water Quality/Watersheds Becky Cook Dr. Paul McGinley Dr. Byron Shaw Dick Stephens Nancy Turyk Near Shore Summary Dr. Glenn Bowles Special thanks to UWSP undergraduate and graduate students and local citizens for their assistance! 18